Offset linting is considered to be one of the most serious paper related problems and a source of frequent printer complaints. It is defined as the removal of fibres and fines from the surface of uncoated paper during offset printing, and is a particular issue with sheets from mechanically pulped fibres. The build-up of lint on the printing blanket (as shown in Figure 1) results in the reduction of print quality and can affect the pressroom efficiency. Because the mechanism of linting is not completely understood, linting problem can be difficult to solve.

The broad objectives of this research project are to understand the dynamics of linting during offset printing and how it relates to the paper properties and printing press variables. It will involve the development of image analysis system to measure the transfer of the lint particles during printing process. The study will also investigate the fundamentals of linting mechanism by looking at the characterisation of lint particles adhesion in offset printing, the measurement of ink spreading as a variable that influences linting and the removal of vessel elements linting from the paper surface.

It is anticipated that this study will improve a quality control tool that can provide better correlation between paper measurements and the linting performance of paper products. The work should also help paper mills and printers to understand the dynamics of lint migration during offset printing and the mechanisms behind linting occurrence.

Figure 1. An Example of lint build-up captured by the lint camera during a press run. (A) Dynamic images at the very beginning of run; (B) Dynamic images at 500 copies; (C) Dynamic images at 6900 copies. Press speed was 8000 copies an hour.

Lestiani, R., Batchelor, W., and Banham, P. (2013). Investigation of the performance of a lint camera system in identifying lint using image analysis. Appita Journal: Journal of the Technical Association of the Australian and New Zealand Pulp and Paper Industry, 66(4), 299-305. Link

Lestiani, R., Batchelor, W., and Banham, P. (2013). "Effects of paper and printing press variability on the dynamics of linting", Oral presentation at the 40th International Research Conference of iarigai: Digitalization of Print Exchanging Ideas across Generations, Chemnitz, Germany.